Transmission mechanism



TRANSMISSION MECHANISM Filed Feb. 9. 1926 FIG-1.

, 1N VEN T011. 74mm. 2.1,@ 4me;

BY @www A TTORNEYS.

Farmaci c. e, i927.

HERBERT L. JOHNSTON, OF TROY, OHIO, ASSIGNOR TO THE HOBART MANUFACTURINGCOMPANY, OF TROY, OHIO, A CORPORATION 0F OHIO.

TRANSMISSION MECHANISIVI.

' Appliqation filed February 9, 192s. serial No. sans.

My invention relates to transmission mechanism and particularly totransmission mechanism embodying yflexible connections and a clutchbetween a revolving driving,

member and speed change gearing adapted to actuate driven members. j c

It is the object of my invention to provide a connection between adriving member and speed change gearing, which connection will bear theshocks incident to intervals of changing c gears without causing unduestrain on the transmission mechanism. It is further my object to providein combination with the flexible connection for a clutching devicebetween, the driving member and the driven member, which will greatlyreduce the likelihood of damage to the mechanism by sudden stoppagessuch as often occur in mixing machines and the like.

Referring to the drawing in which I have illustrated a preferredconstruction embodying my invention Figure 1 is a sectional viewof thetransf mission mechanism.

Figure 2-is a side elevation showing an internally grooved speed changegear with a diving key in inoperative position.

Figure 3 is aside elevation showing the internally grooved speed changegear illustrated in Figure 2 with the diving key in operative position.

Figure 4 is a perspective view of the preferred type of spring by meansof which a' iiexible connection is provided.

Generally indicated at 1 I have shown a casing in which my transmissionmechanism may be suitably encased. The pinion 2 which may be mounted onthe end of a motor shaft, or on any other driving mechanism, engages anddrives a gear 3, which is nonrotatively mounted on ashort shaft 4. Thelower end of the shaft isA slotted as indicated at 5, the slot being ofsuitable size and shape to engage. the end of'a spring 6./ Theparticular shape of the spring member which I have found most effectiveis as indicated in which the spring consists of a fiat metallic platewhichmay be twisted along an axial line extending` longitudinallyAtherethrough. A hollow cylindrical member 7 surrounds the spring andprovides a journal for the end of the shaft 4. The member 7 has an.enlarged end 8 which forms the internal portion of a clutch devicewhich will vbe hereinafter described. The end of the memshaft 4 ismounted. The spring is sov mounted that in a vconstruction according tothe one illustrated in which the direction ofv rotation of the gear 3 isclockwise, the normal position of the pin within the slot 9 will be atthe right end of Mthe slot. The enlarged endl of the member 7 has a plugl11 within its hollow interior and the plug maybe fixedly mounted withrelation to the enlarged end of the member 7 by means of a pin 12. `Theplug preferably operates as .if it were an-integral'part ofthe member 7,

and might be except that I have found that the structure may be moreeasily assembled as has been described. A series of radial holes 13 aredrilledaxially through the enlarged end 8 and within the holes I havedisposed hardened steel balls 14, with springs 15 abutting the plug 11tensioned to press the ballsloutwardly through the ends of the radialholes 13. i f

TheY lower end 8 of the memberA 7 is mounted within a. cup shaped member16 which has a hub 17 extendingfrom one end thereof. The hub has mountedwithin it the shaft 18. Interspaced holes 19 corresponding with theholes 13 in the member 8 arek drilled Aradially into the cup shapedmember 16- and I have found it preferable to drill these holes ofslightly less diameter, than the diameter of the balls 14. Arcuategrooves withinA the inner walls of the Wcup shaped member will provideas effective a means of engagingthe balls 14 but I have found thatpthedrilling of the holes permits a much simpler manufacturing operation.

Upon the shaft 18 a pinion 20 is xedly mounted, the preferred securingmeans being, as indicated, a pin slot connection 21. The pinion 20engages a gear 22 mounted on a shaft 23 which'carries the speed changegears. The shaft 23 has milled longitudinally therein a keyway' 24within which is 100 disposed suitable speed change gears such as 105 thegears indicated at 27, 28 and 29. A driven shaft 30 has cooperatinggears 31, 32 and 33 iixedly mounted thereon which gears are meshed withthe gears 29, 28l and 27 re# spectively. In the particular mechanismil-110 of the mounte in a sliding sleeve 35, which has a lustrated thefinal load is carried by Atheportion of the shaft which is shownextending from the casing L Eachl of the gears 27, 28 and 29 has'agroove 34, which is'prei'- erably tapered counter'to ,the diretion ofengagement with the key 25 as indicated in Figures 2-and 3. The key ismovably on the shaft 23 so that the end may be moved into engagementwith the groove in any one ears. The other end of the key is eripheralgroove 36 therein in which a ork or other suitable lever may be securedl to shift from one set-,of gears to another.

The iiexible connection betweenthe driving gear 3 and the member 7 willbe readily understood. The shaft 4 is usually rotated at a fixed speedso that it will be apparent that if there were no exible connectionsbetween the driving and the driven members with the movement of the keyfrom engaging position with one of the gears to another therewould beaninterval when the shaft1 30 would be stationary. Then withv theengagement of thegear there would be lan abrupt jerk which might injurethe vmechanism. With the flexible connection,

however, which I have provided, during intervals of change of gears,with the engagement of any gear the spring 6 will Hex until the pin 10has moved to the left end of the slot 9. The normal operating posi-'.tion of the pin 10 is at the right end of the slot 9, but as soon asthere is any abrupt shockl as occurs at `intervals of changing gears,the pin will move tothe left end of the' slot and the spring will vbeflexed. Should there be a jamming ofthe driven members the clutch deviceformed by the -balls enga ing the holes in the cup shaped member wi lpermit the members 7 and 8 to Y rotate with relation to the cup shapedmemof the drivenl members.

vber until the cause of the stop-page has been corrected. Duringv suchintervals of rotation of the members 7 and 8 with relation to the cupshaped member the balls will slide along the inner wall of the cupshaped -member and as soon as the cause of stop- .neszneaa i poses maybeaccomplished l have disclosed a specific structure which is inexpenslveto manufacture and which gives excellent re- While lf have in theensuing description disclosed one specific embodiment of. my invention,it will beunderstood that its application is not limited to speed changegears but will provide a suitable transmission for any alternatelyengaged and disengaged driven .members Having thus described myinvention, what l claim as new and desire to securel by Letters' Patent,is

1. Transmission mechanism comprising in combination with a drivingmember and a driven memberadapted to be rotatably engaged during theoperation of the driving member, intermediate mechanism consisting ofatorsion spring secured at one end to a driving member and at the otherto a driven member with means of limiting the torque of said` spring andestablishing anon-flexible driving connection at a point of extremetorque of said spring, and said spring consisting of at least one fiatmetallic plate having an axis of torque along a line extendinglongitudinally therethrough.

2. Transmission mechanism comprising in combination with a driving shafthaving a pin projecting therefrom, a flat platepsecured to said shaft,`said plate having an axis of torque along a line extendinglongitudinally therethrough, a hub member having an elongated sleeveportion surrounding and acting as a bearing'for said shaft, said hubmember having a series of radial holes with balls resiliently pressedoutwardly within the holes, a housing enclosing said vhub having aseries of holes therein in alignment with the path of movement of theballs during the rotation of said hub, an

attaching structure by means of which said housing is connected with ashaft to be driven, and said elongated sleeve portion having a slotwithin which the pin ofthe driving shaft is retained.

3. Transmission mechanism comprising in combination with a driving shaftand a shaft to be driven, a hub having an elongated sleeve portionprovidnnf.- a. bearing for said drivino shaft, a longitudinallytwistable metalllc plate enclosed within said sleeve, a driving portionof an overload clutch connected by said plate with vthe drivingshaft-and a pin and slot connection between said shaft and sleeve.

HERBERT L. JOHNSTON.

